<u>Answer:</u>
The final velocity of the two railroad cars is 1.09 m/s
<u>Explanation:</u>
Since we are given that the two cars lock together it shows that the collision is inelastic in nature. The final velocity due to inelastic collision is given by

where
V= Final velocity
M1= mass of the first object in kgs = 12000
M2= mas of the second object in kgs = 10000
V1= initial velocity of the first object in m/s = 2m/s
V2= initial velocity of the second object in m/s = 0 (given at rest)
Substituting the given values in the formula we get
V = 2×12000 + 0x100012000 + 10000= 2400022000= 1.09 m/s

Which is the final velocity of the two railroad cars
Clarify what you mean by ratios?
Answer:
See below ~
Explanation:
An object will sink in water when its density is greater than that of water, which is 1 g/cm³.
Volume of the box is <u>1331 cm³</u>. (11³)
Maximum mass of sand will be 1331 g. [because 1331/1331 = 1 g/cm³]
- Volume of sand = Mass of sand / Density of sand
- Volume (sand) = 1331/3.5
- Volume (sand) = 380.29 cm³
If the volume of sand is <u>greater than 380.29 cm³</u>, the box will sink in water.
The area is the length times the height so A= bh ...?